Help: I got more problems again

"Dr. Zoidberg - RIP Oppo" (thetomselleck) 03/07/2020 at 19:22 • Filed to: Vibe 2020

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For the last week or so, my wife’s car has had trouble starting. Specifically, cranking but won’t fire which a few attempts . It was intermittent when it decided to do or not do it, but has now done  it the last three times she’s gone to start it. It'll be crank crank crank crank crank give up crank crank crank crank crank try again crank start. The battery is two years old and tests fine. No CEL. Any thoughts?

Cash Rewards > Dr. Zoidberg - RIP Oppo 03/07/2020 at 19:31

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I think NojustNo solved this problem a few posts ago

BrianGriffin thinks “reliable” is just a state of mind > Dr. Zoidberg - RIP Oppo 03/07/2020 at 19:32

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If you’re *sure* it’s not the battery (i wouldn’t be so sure), then I’d say the next thing to check is fuel. Weak fuel pump, clogged fuel filter if it has one, that kind of thing. It runs fine when it starts?

ITA97, now with more Jag @ opposite-lock.com > Dr. Zoidberg - RIP Oppo 03/07/2020 at 19:32

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Make sure you’re getting spark. I’d check fuel pressure on it making sure you don’t have a plugged filter (less likely , if it even has an external filter) or a dying fuel pump (more likely). Also worth making sure the crankshaft position sensor is outputting correctly. Most modern cars use that sensor to both energize the fuel pump and control injector timing, and to fire the coil packs. If it isn’t working, it’s a do not pass go situation.

Dr. Zoidberg - RIP Oppo > BrianGriffin thinks “reliable” is just a state of mind 03/07/2020 at 19:41

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Yes, runs normal when started.

Demon-Xanth knows how to operate a street. > Dr. Zoidberg - RIP Oppo 03/07/2020 at 20:03

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Check valve in the fuel pump. If it doesn’t start quickly, pause, turn the key to on, wait a second, then try again. This happened to my 2004 Grand Prix. What happens is that when the check valve fails it lets the fuel rails run dry and you have to refill them. The fuel pump only runs for a few seconds during each attempt. So it takes multiple attempts to get enough fuel up to build pressure.

The fix is to replace the fuel pump assembly.

ItalianJobR53 - now with added 'MERICA and unreliability > Dr. Zoidberg - RIP Oppo 03/07/2020 at 20:03

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Apart from fueling and spark, check cam and crank position sensor. If one of them is bust, the ECU will need more cranks to determine whats the position of the valves to decide fuel injection and spark timing.

We forgot to connect the cam position sensor on my friend’s car and it did require a lotta cranking to get started but worked fine after that.

The Snowman > Dr. Zoidberg - RIP Oppo 03/07/2020 at 20:07

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Swap batteries with another car to rule that out(I know you have a spare car)  Then look at fuel if it's still happening.

Demon-Xanth knows how to operate a street. > Demon-Xanth knows how to operate a street. 03/07/2020 at 20:21

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Side note: this can be verfied with a fuel pressure gauge attached to the fuel rail (how I diagnosed mine). Also, if you want a Pontiac factory service manual on DVD, and the other GM makes if you know your way around a Windows NT virtual machine, let me know and I can mail you mine.

SmugAardvark > Dr. Zoidberg - RIP Oppo 03/07/2020 at 22:30

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Obviously a very different car , but this is exactly what my Subaru SVX started doing just before the in-tank fuel pump gave up the ghost.

Which of course happened immediately after filling the tank.

Dogsatemypants > Dr. Zoidberg - RIP Oppo 03/08/2020 at 00:00

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Check the fuel pressure sounds like a good idea. I would also suggest checking the relays for the ignition and fuel pump. Intermittent failure can be a sign of the relay going bad.

Dr. Zoidberg - RIP Oppo > Demon-Xanth knows how to operate a street. 03/08/2020 at 01:18

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Is the fuel rail not to be confused with the fuel pressure test port accessible under the hood? Remember: I’m not too bright about actual car thingies...

pip bip - choose Corrour > Dr. Zoidberg - RIP Oppo 03/08/2020 at 05:19

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crank sensor?

cam sensor?

RallyDarkstrike - Fan of 2-cyl FIATs, Eastern Bloc & Kei cars > Dr. Zoidberg - RIP Oppo 03/08/2020 at 08:09

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My Accent did this the other year...was because a ground strap between two parts of the starter was rusting off due to winter salt, but it happened in like late summer/fall.

Demon-Xanth knows how to operate a street. > Dr. Zoidberg - RIP Oppo 03/08/2020 at 15:13

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On my Grand Prix, the test port was on the fuel rail. So the test port is plenty good. You should see it jump up to something like 75PSI if it is good on the first key on. If it goes 25 on the first, 40 on the second, 55 on the third, your lines were drained.

SBA Thanks You For All The Fish > Dr. Zoidberg - RIP Oppo 03/09/2020 at 20:37

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The best $20 I spent last year was a set of “Noid Lights”... basically flashing LED lights with the proper connector termination to sit on a plug lead (to see if it’s firing) or another type on an injector plug to see if the PCM is firing the injectors.

If BOTH are flashing while cranking? Almost has to be fuel pressure.

It’s an easy, almost-perfect base-level test setup.

If you have both flashing?  I’d go fuel pump and filter next.  If OK, check pressure on the rail.

SBA Thanks You For All The Fish > Dr. Zoidberg - RIP Oppo 03/09/2020 at 20:38

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